Evaluation of anti-nociceptive activity of methanolic extract of Tecomaria capensis Thunb.(Bignoniaceae) leaves in rats

Objective:To evaluate the ann-nociceptive activity of Tecomaria capensls(T.capensis) leaves extract(TCLE) using different models in rats by acetic acid induced writhing test,(b) tail-flick test(c) tail-clip test.Methods:TCLE(100,300,1000 and 2000 mg/kg body wt.) was given to rats orally to observe acute toxicity for 14 d.Then test drug TCLE were given at dose of 100,200 and 500 mg/kg p.o.and standard drug aspirin were given at a dose of 100 mg/kg p.o.Results:No mortality was reported even after 14 d.This indicates that the methanol extract is safe up to a single dose of 2 000 mg/kg body weight TCLE(100,200 and 500 mg/kg p.o.) significandy inhibited abdominal constrictions(writhing) induced by acetic acid and increased the latency period in the tail flick and tail clip test.TCLE at the dose of 500 mg/kg showed significant anti-nociceptive activity compared to standard aspirin.Discussions:The results of this study show that methanol extract of T.capensis possesses anti-nociceptive activity which may be mediated by the central and peripheral mechanisms.

Tolerance effects of non-steroidal anti-inflammatory drugs microinjected into central amygdala,periaqueductal grey,and nucleus raphe Possible cellular mechanism

Pain is a sensation related to potential or actual damage in some tissue of the body. The mainstay of medical pain therapy remains drugs that have been around for decades, like non-steroidal anti-inflammatory drugs （NSAIDs）, or opiates. However, adverse effects of opiates, particularly tolerance, limit their clinical use. Several lines of investigations have shown that systemic （intraperitoneal） administration of NSAIDs induces antinociception with some effects of tolerance. In this review, we report that repeated microinjection of NSAIDs analgin, clodifen, ketorolac and xefocam into the central nucleus of amygdala, the midbrain periaqueductal grey matter and nucleus raphe magnus in the following 4 days result in progressively less antinociception compared to the saline control testing in the tail-flick reflex and hot plate latency tests. Hence, tolerance develops to these drugs and cross-tolerance to morphine in male rats. These findings strongly support the suggestion of endogenous opioid involvement in NSAIDs antinociception and tolerance in the descending pain-control system. Moreover, the periaqueductal grey-rostral ventro-medial part of medulla circuit should be viewed as a pain-modulation system. These data are important for human medicine. In particular, cross-tolerance between non-opioid and opioid analgesics should be important in the clinical setting.

Comparison of the Analgesic Activity of Antiparkinsonian Aminoadamantane Derivatives Amantadine and Hemantane

The efficacy of some aminoadamantane derivatives used as neurodegeneration treatments is due to their ability to block NMDA receptors. But this mechanism of pharmacological action can also produce analgesic activity. Analgesic properties of two aminoadamantanes, amantadine (20 mg/kg) and hemantane (20 mg/kg), which were uncompetitive NMDA receptor antagonists, were assessed in rodent models of pain induced by different pain stimuli (tail-flick test, acetic twitches test in mice and formalin test in rats). Additionally, the anti-inflammatory properties of hemantane and amantadine were evaluated in mice with acetic peritonitis and in rats with hind paw edema induced by formalin injection. The results of our study demonstrate that the analgesic activity of the 1-aminoadamantane amantadine differs from the 2-aminoadamantane hemantane. The analgesic activity of amantadine administered intraperitoneally was more pronounced in the case of acute thermal pain in mice compared to hemantane, and only amantadine had a significant analgesic effect on the acute early phase of formalin pain in rats induced by the effect of the algogen on the primary sensory afferents. Hemantane was more effective than amantadine for relieving pain produced by inflammation owing to its pronounced anti-inflammatory activity: only hemantane decreased the amount of acetic twitches in mice that received drugs orally and was effective in the tonic phase of formalin pain in rats.

Anti-inflammatory Effect of Heat-sensitive Moxibustion via the NF-κB Signaling Pathway on Cerebral Ischemia/Reperfusion Injury in Rats

Ischemic stroke is universally acknowledged as a common cause of long-term disability or even death. Suspended moxibustion, an indirect form of moxibustion, is when moxibustion is placed superficially over the skin without being in contact with it. Some researchers have used this method to treat stroke patients, but strong evidence of its therapeutic effectiveness is lacking. However, the effect of traditional suspended moxibustion has recently been improved with the development of heat-sensitive suspended moxibustion. Our previous studies showed that moxibustion for 35 min provided a more effective treatment strategy than moxibustion for 15 min, and moxibustion by 35 min with tail temperature increase had a better outcome than that without, however, the mechanism underlying the effect is not clear. In this study, we treated the stroke rats with moxibustion by 35min and divided them into non-heat sensitive moxibustion(NHSM) group and heat sensitive moxibustion (HSM) group according to difference in the tail temperature increase, then we compared the effect and investigated the mechanisms between NHSM and HSM. We found that HSM significantly decreased tail-flick latency, increased neurological function score, decreased infarct volume, reduced inflammatory cells, decreased the expression of inflammatory factor ICAM-1 and reduced the expression of NF-κB p65 and p-IKKα/β in rats with focal cerebral ischemia/reperfusion injury. Our experimental findings revealed that HSM exerted its anti-inflammatory and neuroprotective effects from MCAO-induced injury by decreasing the expression of the NF-κB signaling pathway.

Evaluation of Antinociceptive Activity of Methanol Extract from Cleome rutidosperma in Mice

Objective C/eome rutidosperma （Capparidaceae）, commonly known as ＂Fringed Spider Flower＂, is a medicinal plant found in Southeast Asia. C. rutidosperma is used in folk medicine for diuretic, laxative, analgesic, anti-inflammatory, antipyretic, antimicrobial, anti-oxidant, hypoglycemic, and anthelmintic activities. We have evaluated the anti-nociceptive properties of methanol extract from C. rutidosperma （MECR） in vivo. Methods Thermal method （hot plate test and tail flick test） was induced to judge the anti-inflammatory effect and couple of chemical method also used （formalin induced licking test; writhing test carried by acetic acid） to evaluate analgesic effect. Both of these tests were made over animal models, like mice and rats. Two different doses （1 O0 and 200 mg/kg） were used for each case of test, while morphine sulphate （5mg/kg, ip） was used as reference drug. Results MECR demonstrated the significantly anti-nociceptive activity in the analgesic and anti-inflammatory tests by reducing nociception in mice models （P 〈 0.001）. in the hot-plate and tail-flick tests, MECR significantly elongated the time to response to the thermal stimuli （100 and 200 mg/kg with P 〈 0.05, 0.001）. The remarkable increase in the latency was observed at 90 and 120 min. In acetic acid-induced writhing test and formalin induced licking test for anti-inflammatory activity, MECR at 100 and 200 mg/kg doses exhibited significant （P〈 0.001） reduction of writhing and licking response. Conclusion The anti-inflammatory and analgesic effects of C. rutidosperma propose that this effect may be a result of both peripheral and central mechanisms. Further study is required to ensure the proper mechanism of action as well as the active ingredient.